Design, characterization, and control of a large aperture MOEMS Fabry-Perot tunable infrared filter

A miniature Fabry-Perot tunable infrared filter under development at the NASA Goddard Space Flight Center is fabricated using micro opto electromechanical systems (MOEMS) technology. Intended for wide-field imaging spectroscopy in space flight, it features a large 10-mm diameter aperture structure that consists of a set of opposing suspended thin films 500 nanometers in thickness, supported by annular silicon disks. Achieving the desired effective finesse in the MOEMS instrument requires maximizing the RMS flatness in the film. This paper presents surface characterization data for the suspended aperture film prior to, and following application of a multi-layer dielectric mirror. A maximum RMS flatness of 38 nanometers was measured prior to coating, leading to an estimate of the maximum effective finesse of 14. Results show evidence of initial deformation of the silicon support structure due to internal stress in the substrate and thin film layers. Film stress gradients in the dielectric coating on either side of the aperture add convexity and other localized deflections. The design of a tuning system based upon electrostatic positioning with feedback control is presented.

[1]  Larry K. Baxter,et al.  Capacitive Sensors: Design and Applications , 1996 .

[2]  José Higino Correia,et al.  Micromachined Fabry-Perot optical filters , 1998, ASDAM '98. Conference Proceedings. Second International Conference on Advanced Semiconductor Devices and Microsystems (Cat. No.98EX172).

[3]  J. Seeger,et al.  Stabilization of electrostatically actuated mechanical devices , 1997, Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97).

[4]  Matthew A. Greenhouse,et al.  Micromachined tunable Fabry-Perot filters for infrared astronomy , 2003, SPIE Astronomical Telescopes + Instrumentation.

[5]  Matthew A. Greenhouse,et al.  Electromechanical simulation of a large-aperture MOEMS Fabry-Perot tunable filter , 2000, SPIE MOEMS-MEMS.

[6]  R. Howe,et al.  Multimode digital control of a suspended polysilicon microstructure , 1996 .

[7]  J. Patterson.  Micro-Mechanical Voltage Tunable Fabry-Perot Filters Formed in (111) Silicon. Degree awarded by Colorado Univ., Boulder, CO , 1997 .

[8]  José Higino Correia,et al.  Bulk-micromachined tunable fabry–perot microinterferometer for the visible spectral range , 1999 .

[9]  Matthew A. Greenhouse,et al.  Near-IR Fabry-Perot interferometer for widefield low-resolution hyperspectral imaging on the Next Generation Space Telescope , 2000, Astronomical Telescopes + Instrumentation.

[10]  D. Ciarlo,et al.  A Fabry-Perot microinterferometer for visible wavelengths , 1992, Technical Digest IEEE Solid-State Sensor and Actuator Workshop.

[11]  S. R. Mallinson,et al.  A miniature Fabry-Perot interferometer with a corrugated silicon diaphragm support , 1991 .

[12]  E. Mozdy,et al.  Surface micromachined Fabry-Perot tunable filter , 1996, IEEE Photonics Technology Letters.

[13]  T. R. Hicks,et al.  The application of capacitance micrometry to the control of Fabry-Perot etalons , 1984 .

[14]  Matthew A. Greenhouse,et al.  SIMULATION OF AN ELE CTROSTATICALLY ACTUA TED MICRO -MACHINED FABRY -PEROT ETALON , 2002 .

[15]  Nasser Peyghambarian,et al.  Tunable Fabry-Perot Filters using Electro-Optic Hybrid Sol-Gel , 2006, 2006 European Conference on Optical Communications.